Five years after his wife, Joan, had him wrongfully and delibarately committed to a mental institution so she could live with her boyfriend, Malcolm escapes on Halloween night and arrives back at his old house to murder her, except Joan is not home but she's out with her boyfriend while babysitter Linda is looking after Malcolm's 10-year-old son Christopher, an equally psychotic and demented practical joker until, under cover of darkness, Malcolm shows up and begins a real terror game of attrition with Linda.